Vacuum producing apparatus



Nov. 13, 1934. H. M. GRAHAM VACUUM PRODUCING APPARATUS 2 Sheets-Sheet l Filed March 23, 193E INVENTOR .M/WHM 694720111 l jofa' MA l m ATTORNEYS Nov. 13, 1934. H. M. GRAHAM VACUUM PRODUCING APPARATUS 2 SheetsSheet 2 Filed March 25, 1953 Patented Nov. 13, 1934 VACUUM PRODUCING APPARATUS Harold M. Graham, Buflalo, N. Y., assignor, by

mesne assignments, to Ross Heater &.Manufactoring Company, Inc., Buffalo, N. Y., a corporation of New York (1933) Application March 23,1933, .Serial No 662,279

9 Claims.

This invention relates to improvements in vacuum producing apparatus. While the invention is not necessarily so limited, it is characterized by features which render it of particular 5 utility in connection with the maintenance of a fluid medium, for example a refrigerant, at a temperature of a predetermined value. More particularly the invention is concerned. with apparatus of the kind in which the maintenance of the vacuum in the working chamber is accompanied by a partial vaporization of the fluid medium.

The apparatus, in general, includes a working chamber into which the fluid medium is intro- 1 duced, a plurality of ejectors for creating and maintaining a vacuum in the working chamber and a common condensing chamberinto which the ejectors discharge and in which the steam and that portion of the fluid medium which is 0 vaporized and entrained are condensed, the ejectors being so designed that certain or all of them may be rendered operative and inoperative at will.

One object of the invention is to provide a novel arrangement of the ejectors, whereby the capacity of the apparatus may be increased and decreased as occasion demands.

A further object is to prevent backflow between the condensing chamber and the working chamber when any of the ejectors are inoperative.

A still further object is to provide apparatus in which an inoperative ejector is automatically rendered operative in the event that the possi- .3 bility of a backflow arises.

A still further object is a novel design and arrangement of the parts of the apparatus whereby simplicity and economy in construction are obtained.

The invention is characterized by features which render it of particular advantage in connection with refrigerating systems, air conditioning apparatus, water cooling and similar systems. It is to be understood, however, that 5 the advantages of the invention may be obtained in connection with other types of apparatus, the uses specifically noted being intended to be by way of example only.

The invention is illustrated in the accompany- 0 ing drawings, in which:-

Figure 1 is a plan view of apparatus embodying features of the invention.

Figure 2 is an enlarged detail view, partly in section, of the valve control mechanism which is .55 employed in connection with the ejectors,

Figure 3 is a longitudinal vertical section through the apparatus.

The invention is illustrated in connection with a refrigerating system, the latter being sufficiently indicated by a showing of the cooling i: chamber 5 thereof. The refrigerating medium is conducted to the cooling chamber by a pipe 6 and is introduced into the chamber in the form of a spray, a predetermined volume of refrigerant being maintained in the chamber by a float con- 51} trolled valve 7. The refrigerant is drawn from the cooling chamber through a pipe 8 by a suitable pump 9, the latter being availablev to circulate the refrigerant through the cooling. coils of the system. In this connection it is understood, of course, that the liquid which is introduced into the cooling chamber through .the pipe 6 may be the liquid which is circulated through the cooling coils or it may be liquid which is obtained from an independent or remote '15s source.

The refrigerating medium in the chamber 5 is lowered to and maintained at a predetermined temperature by maintaining a predetermined vacuum in the said chamber, for example a pres-. sure of the order of 29.75". To this end a plurality of ejectors 10 are employed. Each of the ejectors includes one or more nozzles 11 to which steam is supplied from a pipe 12, the latter com municating with a main supply pipe 13. The ejectors communicate with the chamber. 5 by way of conduits 14, the steam whichis discharged from the nozzles 11 and the entrained portions of the vaporized medium from the chamber 5 being discharged through the throats 15' of the ejectors into a condenser 16. The cooling chamber 5 and condenser 16 are, as illustrated, provided with suitable headers 17 and 18, respectively, whereby to facilitate connection of the ejectors and conduits 14 thereto, the header 18 being suitably provided with extensions 19 to, which the throats of the ejectors are connected.

A vacuum, for example, of the order of 28" of mercury is preferably maintained in the condenser 16. To this end an ejector 20 is employed. 1.00 The latter includes a nozzle 21 which is connected, bya pipe 22 to the steam supply line 13. The ejector communicates with the condenser 16 through a pipe 23 and discharges into a chamber Ma of an auxiliary condenser 24, a vacuum being maintained in the said chamber by an ejector 25 which is connected to the steam supply line 13 by a pipe 26. The ejector 25 discharges into a second chamber 241) of the condenser 24, the saidsecondchamber being in communica- 11 tion with the atmosphere through an air vent 27. The head 28 of the condenser 16 is formed with inlet and outlet chambers 29 and 30, respectively. The former is connected to a pipe 31 by which cooling Water is introduced into the inlet chamber 29. The water which is introduced into the chamber 29 passes from the inlet chamber through the tubes in thelower half of the condenser into the head 32 of the condenser. From the head 32 the Water flows through the tubes in the upper half of the condenser into the outlet chamber 30. From the outlet chamber the water is conducted to a suitable point of disposal by a pipe 33. is circulated through the auxiliary condenser 24 in substantially the same manner as described in connection with the condenser 16, the cooling water being introduced into the condenser by a branch pipe 34 and being discharged therefrom through a branch pipe 35. The condensing chamber of the condenser 16 is provided with an outlet connection 36. Condensate from the condensing chamber is withdrawn through the connection 36 by a pump 37, the pump including a pipe section 38 which is suitably connected to the outlet connection. The outlet 39 of the pump 37 is-connected to a conduit 40 which is adapted to conduct the condensate to a convenient point of disposal. The condensate from the condensing chambers of the auxiliary condenser 24 may be withdrawn and disposed of in any suitable manner. 1

i The work to be performed by the ejectors in maintaining the required vacuum in the evapo rating chamber is dependent among other factors upon the temperature of the cooling medium when introduced into the chamber and the rate at which it is introduced into the evaporating chamber. The work required is also dependent upon the temperature of the cooling water which is circulated through the main and auxiliary condensers l6 and 24, respectively. It will be apparent, therefore, that the equipment must be capable of functioning in the required manner under varying load conditions. The supply pipe 12 of each ejector includes avalve 41, whereby steam may be delivered to the nozzles of only.

so many of theejectors as is necessary to perform the required work under the prevailing operating conditions.

.Under normal operating conditions a higher vacuum is maintained in the cooling chamber 5 than'in the condenser 16. In accordance with the invention, therefore, means is provided to prevent a backflow which would otherwise take place between the condenser and the cooling chamber through the inoperative ejectors and the conduits through which they communicate with the cooling chamber. To this end each conduit is preferably formed or provided with a trap 42 through which the entrained vapors pass when the ejectors are operating. The trap may be filled with water or any other suitable liquid to provide a seal in the conduit which will prevent a backflow between the condenser and the cooling'chamber when the ejector is inoperative. The said liquid may be introduced into the trap through a pipe 43 which includes a suitable valve 44. The liquid which is introduced into the trap partially fills both of the legs thereof,

the difference in heights of the columns of liquid in the legs of the trap depending upon the difference in pressures in the condenser and the cooling .chamber. The trap 42 is-connected by a I pipe 45 to the cooling chamber. The said pipe Cooling Water from the'pipe 31 In accordance with the invention the closing of the steam supply valve of an ejector is effected automatically with and as an incident to the formation of a seal in the trap which is associated with the ejector. To this end the operating stem 47 of a valve 41 is connected to an arm 48 which is suitably mounted upon the casing of the valve. The arm 48 is connected by an adjustable link 49.- to an arm 50 which is fixed to a shaft 51. The said shaft is suitably mounted in a housing 52 which is secured to a lateral extension 53 of the trap. A float 54 which is arranged in the trap is connected by an arm 54a to the shaft 51. The float 54 occupies the dotted line position shown in Figure 3 when the valve 41 is open and the ejector is operating. Thefloat 54 is so designed that when thetrap 421s filled in the manner described it is elevated by; the liquid which provides the seal to the full-line position shown in this figure. In this position the valve 41 is closed and the supply of steam to the nozzle 11 is, therefore, cut off. When it is desired that the ejector again become operative the valve 46 may be opened tov permit the liquid in the trap 42 to drain into the chamber 5. As the float 54 lowers the valve 41 is opened and steam is deliveredto the nozzle 11. The trap is preferably provided with a suitable gauge 55 by which the height of the liquid seal in the trap is indicated. i

When the apparatus is in use, assuming that all of the ejectors are operating, and it is desired to cut out one of the ejectors, the drain valve 46 which is associated with the conduit which includes the said ejector is closed. The valve 44 is then opened to admit liquid into the trap from the supply pipe 43. As the liquid rises in the trap and approaches the desired height the float 54 is lifted to operate the valve 41 and cut off the supply of steam to the ejector. The liquid which enters the trap, therefore, serves to prevent a back flow from the condenser to the Working chamber 5 and at the same time cuts off the supply of steam to the ejector. When it is desired that the ejector again be rendered operative, the drain valve 46 is opened to permit the escape of the liquid in the trap. As the liquid drains from the trap the float 54 lowers and the steam supply valve 41 is, operated to again admit steam to the ejector. Hence when the liquid seal in the trap 42 is broken the ejector again co-operates with the remaining ejectors in maintaining the desired degree of vacuum in the working chamber.

From the foregoing it will be apparent that the ejectors may be rendered operative or inoperative as occasion requires. The number of ejectors operating, therefore, may be varied withfacility in accordance with the'work to be performed; As'the closing of the steam supply valve of an ejector is automatically effected when the liquid seal in the trap associated with the ejectorhas reached the required height backflow from the condenser to the cooling. chamber is prevented. In other words the supply of steam to, an ejector is not cut off until an adequate seal is provided between the condenser and the coolingchamber. In the event that the liquid .sealinthe trap lowers as a result of evaporation to such an extent that the possibility of a backfiow arises the valve 41 is automatically opened to admit steam to the nozzle 11 and prevent such backflow.

I claim as my invention:

1. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including means providing a plurality of paths of communication between said chamber and said condenser, ejectors included in said paths, said ejectors discharging into said condenser, means for rendering one of said ejectors inoperative and means for creating a liquid seal in the path of communication which includes said last named ejector, whereby to prevent a back flow through the path which includes the inoperative ejector when another of said ejectors is operative.

2. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits connecting said chamber and said condenser, each of said conduits being provided with a trap, ejectors included in said conduits, said ejectors discharging into said condenser, means for rendering one of said ejectors inoperative and means for creating a liquid seal in the trap of the conduit which includes said last named ejector, whereby to prevent a back flow through the conduit which includes the inoperative ejector when another of said ejectors is operative.

3. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits connecting said chamber and said condenser, said conduits being provided with U- shaped traps, ejectors included in said conduits, said ejectors discharging into said condenser, means for rendering one of said ejectors inoperative and means for creating a liquid seal in the trap of the conduit which includes said last named ejector, whereby to prevent a back flow through the conduit which includes the inoperative ejector when another of said ejectors is operative.

4. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits connecting said chamber and said condenser, ejectors included in said conduits, said ejectors discharging into said condenser, control means for rendering one of said ejectors inoperative and means for creating a liquid seal in the conduit which includes said last named ejector, whereby to prevent a back flow through the conduit which includes said ejector, said control means being connected to said last named means so that upon creation of said seal, said ejector is automatically rendered inoperative.

5. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits connecting said chamber and said condenser, said conduits being provided with traps, ejectors in said conduits, said ejectors discharging into said condenser, control means for rendering one of said ejectors inoperative and means for creating a liquid seal in the trap of the conduit which includes said ejector, whereby to prevent a back flow through the conduit when said ejector is inoperative, said control means being connected to said last named means so that said ejector is automatically rendered inoperative upon the creation of said seal.

6. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser in which a vacuum is maintained, said equipment including a plurality of conduits connecting said chamber and said condenser, ejectors included in said conduits, said ejectors discharging into said condenser, one'of said conduits being provided with a trap, avalve for rendering inoperative the ejector in the conduit which includes said trap, control mechanism for said valve including a float which is arranged in said trap and means for creating a liquid seal in said trap, whereby to prevent a back flow through the conduit which includes said trap when the ejector in said conduit is rendered inoperative,

said valve being connected to said control mech-' anisms so that the said ejector is automatically rendered inoperative upon creation of said seal.

7. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits which connect said chamber and said condenser, ejectors included in said conduits, said ejectors discharging into said condenser, means for rendering an ejector inoperative, means for creating a liquid seal in the conduit which includes said ejector, whereby to prevent a back iiow through the conduit when said ejector is inoperative and another of said ejectors is operative and means for draining the liquid of said seal into said chamber.

8. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plurality of conduits which connect said chamber and said condenser, ejectors included in said conduits, said ejectors discharging into said condenser, means for rendering any one of said ejectors inoperative and means for creating a liquid seal in any one of said conduits whereby to prevent a backfiow through the conduit which includes an inoperative ejector when any of the remaining ejectors are operating.

9. Ejector equipment for evacuating a chamber and adapted to be employed in connection with a condenser, said equipment including a plural ity of conduits which connect said chamber and said condenser, said conduits being provided with traps, ejectors included in said conduits, said ejectors discharging into said condenser, means for rendering any one of said ejectors inoperative and means for creating a liquid seal in any one of said traps, whereby to prevent a back flow through the conduit which includes an inoperative ejector when any of the remaining ejectors are operating.

HAROLD M. GRAHAM. 

